The woman uterus in normal anteversoflexion position is supported by round ligaments to the fundus and its abdominal wall, and by the utero-sacral ligaments to the sacrum. Utero-sacral ligaments determine the position of the cervix. Parametrium ligaments form two fan shape structures which are laterally positioned and fix the uterine cervix and the vaginal vault to the pelvis. Paravaginal ligaments are also laterally positioned and passively hold upper third part of the vagina and actively hold the lower two thirds. Any lesion to this system causes a drop of the uterus and the vagina, which is called prolapse.
The prolapse of the uterus and in its absence of the vaginal vault, what is called utero-vaginal prolapse, have three clinical phases: TYPE I, in which the drop is slight without reaching the vaginal introitus; TYPE II, in which the drop is pronounced and the uterus enters the vaginal introitus; and TYPE III, in which the drop is total and the uterus is out of the external genitals. TYPE II and III prolapses are easily diagnosed, however TYPE I, is difficult to discover and usually goes undetected.
There are no prior art intra-vaginal instruments for measuring a utero-vaginal prolapse. The only prior art instruments pertinent to this area are the instruments adapted for dimensional measurement of uterine and pelvimetrical cavity. The following U.S. patents disclose developments in this field: U.S. Pat. No. 4,121,572 Krzeminski and U.S. Pat. No. 4,685,474 Kurz et al. Both instruments are created to be introduced inside the uterus, through the cervix to obtain one (Krzeminski) or two (Kurz et al.) internal measurements of the uterus cavity. The Krzeminski's and the present invention are both gynecological measuring instruments, so both have measuring scales, although located in different parts. The principal difference is a functional construction adapted to the specific purpose for which they served. Krzeminski's invention consists of two principal parts: a probe with measuring indicia and a horseshoe-shaped body. According to Krzeminski's invention an uterine sound is introduced into the uterus for a measurement of its depth. The distal end of this sound is no more than 2-3 mm, to be able to pass through the cervical os. The measurement is taken by moving the sound only in one direction into the uterus. The most important parts of Krzeminski's invention are the internal stop elements which allow to avoid any displacement and to maintain the precise measurement, once the sound is taken out of the uterus. No measurement different than the depth of the uterine cavity can be taken with this instrument. It cannot be simply placed into the uterus without additional help of other gynecological instruments. First the vagina must be opened by a speculum and than a clamp must be used to enter a spherically-shaped nub of the sound's probe into the cervical os. Such operation needs antiseptic means, is invasive and painful and can even require anaesthesia. The measurement is taken by the examiner without the woman's active participation. The Kurz et al., invention's objective is similar to the Krzeminski's but it is more complex, because two measurements of the uterus can be taken, depth and width.
The present invention is an intra-vaginal prolapse diagnostic instrument only, which cannot be introduced into the uterus, because the plunger which is placed into the vagina is too wide, as it has minimum diameter of 1.5 cm. The measurement is taken in a totally different way, from Krzeminski and Kurz. The present invention consists of three principal parts all of which must be set on a common point, before the measurement can be performed. In the case of the Krzeminski invention a probe is simply pressed ahead into the uterus by the examiner and the resistance of the uterus wall determines the measurement. The present invention however, is to be placed into the vagina first, set in the common point and afterwards the woman is asked to strain. Such action expels the plunger indicating on the outer scale a precise measurement. The plunger moves outside the woman's body, exactly in the opposite direction to the Krzemnski's uterine sound. The present invention does not have any stop elements, and all its parts are concentric and are slidable without any friction in both directions. It can be placed into the vagina without use of any gynecological instruments, without antiseptic measures and without anaesthesia, as this instrument is not an invasive one, and does not cause any pain during the examination. The examiner needs however an active participation of the woman on whom the examination is performed.
Other pertinent prior art patents are U.S. Pat. No. 4,362,167 Nicolai, for measurement of the pelvimetrical cavity, which measures the internal traverse interischial spinous diameter of pelvis of pregnant women as an indication of whether vaginal or cesarean delivery should be performed and the U.S. Pat. No. 3,478,435 Cook, for measuring the thickness of animal tissues, which is an invasive and traumatic instrument adapted to be introduced through skin, fat and muscle implying a blind penetration through different tissues of the animal's body with probable lesions of blood vessels and nerves in any anatomic region excluding natural cavities such as vagina and uterus and its objective is to define an animal's corporal weight.
There are as well methods to detect utero-vaginal prolapse, however they imply x-ray cystograms, x-ray vaginograms and x-ray rectograms which are expensive, time consuming and can have side effects by exposing a woman's body to different x-ray radiations.
The present invention is inspired by the anatomical experiment performed in 1935 by William Mengert, who applied cuts and cross-sections of the different ligamental pairs of support of the uterus in several cadavers of women without prolapse, using a clamp adapted to the cervix of the uterus, a pulley and a ruler, and obtained measurements in centimeters of the displacements that occured when each supporting ligament was cut. These experiments laid the anatomical basis for the significance of measuring and quantifying in centimeters each support ligament of the uterus and the vagina. There is a direct and proportional relation between utero-vaginal ligamentary sufficiency. The objective of this invention is to provide an instrument for easy and rapid diagnosis of prolapse. The principal objective is to detect prolapse in its early stage of TYPE I, which generally is not detected with present techniques. The instrument is also useful for post-operatory follow up to determine the success of surgical techniques in cases where the surgery was performed.